1. Field
Apparatuses and systems consistent with the disclosure relate to a wireless power supply apparatus, a wireless charging apparatus, and a wireless charging system using the same, which can recognize the existence of a subject of charging.
2. Description of the Related Art
Recently, the development of wireless power transfer technology has been accelerated. At present, a general technology of implementing wireless power transfer may be classified into an induction type and a resonance type. The induction type wireless power transfer has been commercialized to produce corresponding products, but the resonance type wireless power transfer has not been greatly commercialized.
Although the resonance type wireless power transfer has a wide application range in degree of freedom of position and distance, it has several disadvantages. Particularly, currently, using the resonance type wireless power transfer, it is unable to recognize whether a receiving device that can wirelessly receive power exists.
Referring to FIG. 1, if a receiver 20 that can wirelessly receive power comes into the neighborhood of a transmitter 10, the transmitter 10 that can wirelessly transfer power transfers power using a general principle of wireless power transfer. However, in the case in which the receiver 20 moves out of the neighborhood of the transmitter 10, the transmitter 10 cannot recognize this, and continuously maintain its maximum power. This may cause unnecessary power consumption.
In order to prevent such unnecessary power consumption, it is required to turn off the power of the transmitter 10 in the case in which the receiver 20 goes away from the transmitter 10 or in the case in which the power charging to the receiver 20 is completed, and this causes inconvenience.